Author Topic: Adjustable Penobscot Møllegabet 52#-75#@28"  (Read 5449 times)

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Offline BowEd

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #15 on: December 27, 2021, 07:13:21 am »
The full draw picture as mentioned definitely shows more bend in the outer limbs just ahead of the lever fade.An area of the limb that does'nt store as much energy as the inner limbs,but does relieve the work the inner limbs do.It's good that you extended the width all the way to the lever fade.
I personally think the inventers of such type bow did what they had to with the wood they had around them to get what they wanted.
All in all you did a fine job.
Took a few pictures of the widths of 2 different bows on the levers.Osage and elm.Measured 9" back from tips and at tips.
The devil can be in the details when reducing these.
The fps gain from testing from removal of material I've found too is right in the perameters of what simk posted.Right around 140 grains of removal[70 grains from each outer limb to tip] gains a person 1 fps.As said earlier too the benefits of a smooth draw and dead in the hand release is noticeable.
mm measurements.
osage



elm



longer levers/shorter working limb like this on elm will make both aspects more noticeable.Thickness and width of lever 1 foot from tips is just a shade over 1/2".A 3" fade at the bottom of lever extends the stiffened portion to around 15" altogether on the bow limb.The bow is 62" TTT.There is around 9" of working limb.

« Last Edit: December 28, 2021, 11:52:48 pm by BowEd »
BowEd
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Ed

Offline Don W

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #16 on: December 27, 2021, 09:47:24 am »
Interesting bow. I like it.
Don

Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #17 on: December 27, 2021, 09:50:14 am »
simk: oh yeah 9,2 :fp
« Last Edit: December 27, 2021, 11:22:48 am by Rowan Bows »

Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #18 on: December 27, 2021, 11:01:08 am »
Tiller with and without the backing attached.

Offline Selfbowman

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #19 on: December 27, 2021, 01:10:58 pm »
That’s a cool bow. The full draw pics with the second limb working and not working was very interesting to me. Just as Ed said about the second limb taking on the stress at inner limbs. Ok sorry guys but what kind of speed are you getting? It does not matter to anyone but me maybe but I’m curious. Arvin
Well I'll say!!  Osage is king!!

Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #20 on: December 28, 2021, 08:34:26 am »
I don´t know it cause after the heat treating I didnt scale it yet. Also I think my Chrony is not reliable. Before the HT the best shot was 52,4m/s with a 28gram arrow but as I said I think these datas are not reliable.
« Last Edit: December 28, 2021, 12:47:27 pm by Rowan Bows »

Offline simk

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #21 on: December 28, 2021, 03:43:12 pm »
thanx for the pics Rowan Bows! It's how we assumed - secondary bow stiffen's up the inners :OK
the longer I'm thinking about this "2-bow system" the more I think this little secondary bow must cause something like a visible stacking in the fdc. How does it feel to draw? If you give me the drawweights of the 75#-version every 2" from 10"-28" I will generate the fdc...?!  (-S It would be very intersting for sure.
Thanx Ed as well. I notice your levers are a 2mm thinner than mine. What cross section are the levers? Mine are kinda trinagle. Glad you got the same numbers for weight/speed correlation. Always dangerous to post any numbers here  ;D

 
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Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #22 on: December 28, 2021, 05:40:25 pm »
the draw is quiet hard with the 75# attached. I always thought like of course its because of the draw weight and the leight of the bow 166cm ntn unstringed. Actually I didn´t even think about the affection of the mainbow tiller untill you brought up this fact. I simply tillered the mainbow and then like "ok lets attach the small one"  :OK
I adjusted the cable leigh so that the whole tiller looked good and shot it and Ive shot it a lot. there are still no compression cracks.  Cant tell something about the force transmitting among this tillershifting but everything seems to be in balance. The levers are stiff till 29cm from the nock then the limb begins to bend.
« Last Edit: December 28, 2021, 06:46:50 pm by Rowan Bows »

Offline bassman211

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #23 on: December 28, 2021, 06:26:55 pm »
Nice conversation piece, but a well built selfbow performs just as well ,or better. I have made a dozen ,or so of them with different lengths, thicknesses, widths from Elm, Hickory, Bamboo, White Oak, and Ash, and have chrony tested each one. Best example I have seen of one was made by Marc S L. He concured with my findings They are fun to make ,and shoot, and they do have adjustable draw weight. Every bow builder should take a crack at least one. You mixed,and matched yours which makes it unique

Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #24 on: December 28, 2021, 06:47:25 pm »
Thank you sir

Offline BowEd

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #25 on: December 29, 2021, 12:04:59 am »
I got the converted numbers stated at 172/fps with a 431 grain arrow[or an 8.3 grain arrow] @ 52#'s? I'm assuming before heat treatment of secondary bow?I don't believe it would have much relevance on outcome though.Main bow maybe yes.
Using a 10 grain arrow[531 grains] I figure the speed to be right around 160/fps.Very respectable.This bow Rowan made should never develop string follow over the years from shooting and shoot the same.
I like to follow up on bows I've made years later and shot a lot every year for durability reasons to see what they perform like.It reveals to me how well I tillered the bow.
Most bows perform best when freshly made.Not everyone shoots the same through the chronograph.Some pause more at full draw than others which can bleed full draw weight a little.Snap shooting usually produces the highest fps readings.Some people are very good at it.Not uncommon to see a 5fps difference between shooters.
simk....Lever depth difference on mine measured at same spot[6" from tip] between osage[1/2"] and elm[9/16"] is 1/16" deeper for elm.Elm is more V shaped.Less depth on osage because of it's density.
 
BowEd
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Ed

Offline Rowan Bows

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #26 on: December 29, 2021, 05:22:18 am »
I shot it with 70#-74# but like I said these numbers are not reliable - I dont trust that chrony. It also says Error everytime. 1 of 5 shots only counts and then it shows really weird numbers too - I wish I did´nt post them. The reason could be anything but I know one thing - all my customers are happy with my bows since 2012. A few shoot competitions with them and since Im so busi at building I became a very bad shooter myself so maybe thats the reason.
But hey I was county champ in 2014 ahh those times :)
Elm is a great wood. Once I had a bug and was almost ready with the bow. The back was clean but I realized a little hole on the side. The result was a labyrinth of bug channels underneath 2 rings from the back. This bow was messed up so I made a breaking test. It behaved almost as if there has never been a violation.
https://www.youtube.com/watch?v=_h7rLImiaIs
« Last Edit: December 29, 2021, 06:24:34 am by Rowan Bows »

Offline BowEd

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #27 on: December 29, 2021, 06:37:57 am »
Yes those numbers at 70-74 pounds do not seem right.Perhaps a new chronograph is needed now.It's ok to be curious of a bows' performance.To me it's just a measurement of my own bow making capabilities.Just because an arrow hisses does not mean it's going fast.That's a different thing causing that.It is like said the chronograph is the unmerciful extractor of truth.I've found years ago shooting in 1 bow after another is'nt good for a persons' form for target shooting either.
Like you said though as long as your customers are happy and they can get accurate with one of your bows.I get follow up communication from people shooting my bows many times.
My main beef is with the FG bow making industry.These self,simple composite,and complex composite bows can and do perform and out perform the FG bows.I personally like seeing owners of FG bows scratch their head when we shoot together.Natural bows will never out perform the compound bows.Neither will the FG bows.
The reliance upon technology IMO hurts the archer in a way to not understand exactly what's going on with a bow and arrow.It does help the industry line their pockets though.Excuse me but I am a very independant cuss.
Good thing about elm is that it does'nt explode.If that were red cedar or cherry or many other woods it would have gone boom.
« Last Edit: December 29, 2021, 08:54:50 am by BowEd »
BowEd
You got to stand for something or you'll fall for anything.
Ed

Offline bradsmith2010

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #28 on: December 29, 2021, 03:09:01 pm »
  sometimes if the light is not right, you will get error readings,, try testing at different time of day,, moving backward or forward a bit till results are consistant,,
if i am in question, I will have someone else shoot with me,, that has a good release,, results can be consistant,, and give you information on what might be improved on,, I use the chrono to hone my skill but it is not the main factor in a good shooting bow,, but I like having the information,,one of my main hunting bows it not great through the chrono,,, but the accuracy makes it my favorite,,, (-S

Offline Selfbowman

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Re: Adjustable Penobscot Møllegabet 52#-75#@28"
« Reply #29 on: December 29, 2021, 10:29:10 pm »
Yep
Well I'll say!!  Osage is king!!